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A Three-Dimensional Heat Transfer Simulation of Laser Full Penetration Welding of Rene-80 Super Alloy
Y. Javid, M. Ghoreishi and S. Shamsaei

A three-dimensional finite element model has been developed to simulate the laser beam welding (LBW) of Rene-80 super alloy and to calculate the transient temperature profile and dimensions of the fusion zone and heat affected zone (HAZ) during the laser welding process. The calculations for the heat transfer problem were performed using the finite element (FE) method. The heat source was the combination of a line heat source through the thickness of the material and a Gaussian heat source on the top surface of the workpiece. This heat source was implemented into the model by a subroutine. The material properties were introduced as temperature dependent due to the high temperature variations and the material phase changes occurring during laser welding. All the major physical phenomena associated with the LBW process such as, heat radiation, thermal conduction and convection heat losses are taken into account in the developed model. For the model validation several experiments were performed with a continuous wave (CW) CO2 laser source. Good agreement between the simulated and the experimental results show that the model would be appropriate for LBW simulation. Also, the results show that the temperature profile and weld bead dimensions are a strong function of the heat source and conductivity of material. It is therefore essential to incorporate an accurate description of the heat source into the model.

Keywords: Rene 80 super alloy, laser beam welding (LBW), finite element (FE) model, heat source model, CO2 laser, simulation

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